The ornamental design for a hydroponictower, as shown and described.
FIG. 1 is a top perspective view of a hydroponic tower showing my new design;
FIG. 2 is a first side elevation view thereof;
FIG. 3 is a second side elevation view thereof;
FIG. 4 is a back elevation view thereof;
FIG. 5 is a front elevation view thereof;
FIG. 6 is a top view thereof; and,
FIG. 7 is a bottom view thereof.
The broken lines shown in the drawings represent a portion of the hydroponic tower or features that form no part of the claimed design.
The broken away symbols in the drawings indicate the appearance of any portion of the article between the break lines forms no part of the claimed design.